In a known design for stabilizing an electric supply system, the controller is adjusted for a defined short-circuit capacity of the system. This system short-circuit capacity can change within broad limits. When this short-circuit capacity changes, the controller works completely inadequately, requiring large nominal-actual deviations to react at all, or it causes controller oscillations. This inevitably leads to system voltage oscillations, which lie within the critical frequency ranges of the system.
There is a need for a method and a device to automatically adapt the controller to the respective operating conditions and to suppress or avoid undesirable controller oscillations and thus voltage variations in the system.